JP2013500597A - Inspection method for lithography - Google Patents

Abstract

A method is provided for determining overlay errors that are subject to the same sensitivity as product features.
The mark used to determine the overlay error includes a subfeature (46) that has a smallest pitch that is approximately equal to the smallest pitch of the product feature. This makes the sensitivity to distortion and aberration the same as that of the product feature. However, when the mark is developed, the subfeatures are combined and only the outline of the larger feature is developed.
[Selection] Figure 6

Description

  The present invention relates to an inspection method that can be used, for example, in the manufacture of a device by a lithography technique, and further relates to a method of manufacturing a device using a lithography technique.

  A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In that case, a patterning device, also referred to as a mask or a reticle, may be used to generate a circuit pattern formed on an individual layer of the IC. This pattern can be transferred onto a target portion (eg including part of, one, or more dies) on a substrate (eg a silicon wafer). Usually, the pattern is transferred by imaging on a radiation-sensitive material (resist) layer provided on the substrate. In general, a single substrate will contain a network of adjacent target portions that are successively patterned. Known lithographic apparatus include a so-called stepper that irradiates each target portion by exposing the entire pattern onto the target portion at once, and simultaneously scanning the pattern in a certain direction ("scan" direction) with a radiation beam. Also included are so-called scanners that irradiate each target portion by scanning the substrate parallel or antiparallel to this direction. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.

  In order to monitor a lithographic process, it is necessary to measure parameters of the patterned substrate, such as overlay errors between successive layers formed in or on the substrate. There are a variety of techniques for measuring the microscopic structures formed in a lithographic process, including using a scanning electron microscope and various specialized tools. One form of specialized inspection tool is a scatterometer that directs a radiation beam to a target on the surface of a substrate and measures the properties of the scattered or reflected beam. By comparing the properties of the beam before and after reflection or scattering by the substrate, the properties of the substrate can be determined. This can be done, for example, by comparing the reflected beam with data stored in a library of known measurements associated with known substrate properties. Two main types of scatterometer are known. A spectroscopic scatterometer directs a broadband radiation beam to a substrate and measures the spectrum of the scattered radiation (intensity as a function of wavelength) in a specific narrow angular range. An angle-resolved scatterometer uses a monochromatic radiation beam to measure the intensity of the scattered radiation as a function of angle.

  [0004] To determine the overlay error between layers, the pattern on the second layer is superimposed on the pattern on the first layer. The radiation beam is then projected onto the pattern and the diffraction pattern is determined. The pattern used to determine overlay error is about a few hundred nanometers while the product feature is about a few tens of nanometers. The projection system from which the projection beam is projected to expose the substrate is not perfect and causes aberrations and distortions. Since some aberrations and distortions are pitch dependent, features with different pitches are projected through different parts of the pupil. Thus, aberrations experienced by product features may not be received by the pattern used to determine overlay error, and vice versa. This can lead to errors in the calculated overlay error, especially when controlling the overlay error using a feedback loop.

  [0005] It would be desirable to provide a method for determining overlay errors that are subject to the same sensitivity as product features.

  [0006] According to an embodiment of the present invention, there is provided a method for measuring a characteristic including the following steps. Projecting a radiation beam having a pattern onto a substrate, the pattern comprising a product comprising a plurality of product features and a mark comprising a plurality of mark features, wherein at least one feature comprises a plurality of subfeatures; Forming a pattern on a substrate, projecting a radiation beam onto the pattern, detecting a diffraction pattern from the pattern, and determining an overlay error between the pattern and the underlying pattern based on the diffraction pattern thing. The subfeature has the smallest pitch that is substantially equal to the pitch of the product feature, and when the pattern is formed, the contour of the mark feature and the product feature is formed, but the shape of the subfeature is not formed.

  [0007] According to a further embodiment of the present invention, there is provided a method for measuring a characteristic comprising the following steps. Projecting a radiation beam having a pattern onto a substrate, the pattern comprising a product comprising a plurality of product features and a mark comprising a plurality of mark features, wherein at least one feature comprises a plurality of subfeatures; Forming the pattern on the substrate. The subfeature has the smallest pitch that is equal to the pitch of the product feature, and when the pattern is formed, the mark feature and the product feature outline are formed, but the subfeature shape is not formed.

  [0008] According to a further embodiment of the present invention, there is provided a device manufacturing method comprising the following steps. Projecting a radiation beam having a pattern onto a substrate, the pattern comprising a product comprising a plurality of product features and a mark comprising a plurality of mark features, wherein at least one feature comprises a plurality of subfeatures; Forming the pattern on the substrate. The subfeature has the smallest pitch that is equal to the pitch of the product feature, and when the pattern is formed, the mark feature and the product feature outline are formed, but the subfeature shape is not formed.

  [0009] Further features and advantages of the present invention, as well as the structure and operation of various embodiments of the present invention, are described in detail below with reference to the accompanying drawings. It should be noted that the present invention is not limited to the specific embodiments described herein. Such embodiments are presented herein for illustrative purposes only. Based on the teachings contained herein, additional embodiments will become apparent to those skilled in the art.

[0010] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate the present invention and, together with the description, explain the principles of the invention and allow those skilled in the art to make the invention. To help you use it.
FIG. 1 shows a lithographic apparatus. FIG. 2 shows a lithographic cell or cluster. FIG. 3 shows a first scatterometer. FIG. 4 shows a second scatterometer. [0015] FIG. 5 illustrates product features and overlay marks according to one embodiment of the invention. FIG. 6 illustrates overlay mark development according to one embodiment of the present invention.

  [0017] The features and advantages of the present invention will become more apparent from the detailed description set forth below when taken in conjunction with the drawings. Here, like reference characters identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and / or structurally similar elements. The drawing in which an element first appears is indicated by the leftmost digit (s) in the corresponding reference number.

  [0018] This specification discloses one or more embodiments that incorporate the features of this invention. The disclosed embodiment (s) are merely illustrative of the invention. The scope of the invention is not limited to the disclosed embodiment (s). The invention is defined by the appended claims.

  [0019] References herein to one or more embodiments to be described and to “one embodiment”, “embodiments”, “exemplary embodiments” and the like are described (one or more). While embodiments of ()) may include particular features, structures, or characteristics, each embodiment does not necessarily include a particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with one embodiment, such feature, structure, or characteristic may be expressed in a different manner, whether explicitly described or not. It is understood that it is within the knowledge of those skilled in the art to perform in the context of the embodiment.

  [0020] Embodiments of the invention may be implemented in hardware, firmware, software, or any combination thereof. Embodiments of the invention may also be implemented as instructions stored on a machine-readable medium that can be read and executed by one or more processors. A machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (eg, a computing device). For example, machine-readable media can be read only memory (ROM), random access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, electrical, optical, acoustic or other forms of propagated signals (eg, carrier waves) , Infrared signals, digital signals, etc.) and others. Further, firmware, software, routines, instructions may be described herein as performing certain actions. However, such descriptions are for convenience only and such acts are actually the result of a computing device, processor, controller, or other device executing firmware, software, routines, instructions, etc. I want to be recognized.

  [0021] Before describing such embodiments in more detail, it is beneficial to illustrate an exemplary environment in which embodiments of the present invention can be implemented.

  FIG. 1 schematically depicts a lithographic apparatus. The apparatus is configured to support and identify an illumination system (illuminator) IL configured to condition a radiation beam B (eg, UV radiation or DUV radiation) and a patterning device (eg, mask) MA. Configured to hold a support structure (eg, a mask table) MT coupled to a first positioner PM configured to accurately position the patterning device according to the parameters of And a substrate table (eg, wafer table) WT coupled to a second positioner PW configured to accurately position the substrate according to certain parameters, and a pattern applied to the radiation beam B by the patterning device MA W target portion C (eg one A projection system configured to project onto includes a die above) (e.g., and a refractive projection lens system) PL.

  [0023] The illumination system may be a refractive, reflective, magnetic, electromagnetic, electrostatic, or other type of optical component, or any of them, to induce, shape, or control radiation Various types of optical components such as combinations can be included.

  [0024] The support structure supports the patterning device, such as by supporting the weight of the patterning device. The support structure holds the patterning device in a manner that depends on the orientation of the patterning device, the design of the lithographic apparatus, and other conditions, such as whether or not the patterning device is held in a vacuum environment. The support structure can hold the patterning device using mechanical, electrostatic or other clamping techniques. The support structure may be, for example, a frame or table that can be fixed or movable as required. The support structure may ensure that the patterning device is at a desired position, for example with respect to the projection system. Any use of the terms “reticle” or “mask” herein may be considered synonymous with the more general term “patterning device.”

  [0025] As used herein, the term "patterning device" refers to any device that can be used to provide a pattern in a cross section of a radiation beam so as to create a pattern in a target portion of a substrate. Should be interpreted widely. It should be noted that the pattern imparted to the radiation beam may not exactly match the desired pattern in the target portion of the substrate, for example if the pattern includes phase shift features or so-called assist features. . Typically, the pattern applied to the radiation beam will correspond to a particular functional layer in a device being created in the target portion, such as an integrated circuit.

  [0026] The patterning device may be transmissive or reflective. Examples of patterning devices include masks, programmable mirror arrays, and programmable LCD panels. Masks are well known in lithography and include mask types such as binary, alternating phase shift, and halftone phase shift, as well as various hybrid mask types. One example of a programmable mirror array uses a matrix array of small mirrors, and each small mirror can be individually tilted to reflect the incoming radiation beam in various directions. The tilted mirror patterns the radiation beam reflected by the mirror matrix.

  [0027] As used herein, the term "projection system" refers to refractive, reflective, suitable for the exposure radiation used or for other factors such as the use of immersion liquid or vacuum. It should be construed broadly to encompass any type of projection system including catadioptric, magnetic, electromagnetic, and electrostatic optics, or any combination thereof. Any use of the term “projection lens” herein may be considered as synonymous with the more general term “projection system”.

  [0028] As shown herein, the lithographic apparatus is of a transmissive type (eg employing a transmissive mask). Further, the lithographic apparatus may be of a reflective type (for example, one employing the above-described programmable mirror array or one employing a reflective mask).

  [0029] The lithographic apparatus may be of a type having two (dual stage) or more substrate tables (and / or two or more mask tables). In such “multi-stage” machines, additional tables can be used in parallel, or one or more tables are used for exposure while a preliminary process is performed on one or more tables. You can also

  [0030] Further, the lithographic apparatus is of a type capable of covering at least a part of the substrate with a liquid having a relatively high refractive index (for example, water) so as to fill a space between the projection system and the substrate. There may be. An immersion liquid may also be added to another space in the lithographic apparatus (eg, between the mask and the projection system). Immersion techniques are well known in the art for increasing the numerical aperture of projection systems. The term “immersion” as used herein does not mean that a structure, such as a substrate, must be submerged in the liquid, but simply the liquid between the projection system and the substrate during exposure. It means that.

  [0031] Referring to FIG. 1, the illuminator IL receives a radiation beam from a radiation source SO. For example, if the radiation source is an excimer laser, the radiation source and the lithographic apparatus may be separate components. In such a case, the radiation source is not considered to form part of the lithographic apparatus, and the radiation beam is directed from the radiation source SO to the illuminator IL, eg, a suitable guiding mirror and / or beam extractor. Sent using a beam delivery system BD that includes a panda. In other cases the source may be an integral part of the lithographic apparatus, for example when the source is a mercury lamp. The radiation source SO and the illuminator IL may be referred to as a radiation system, together with a beam delivery system BD if necessary.

  [0032] The illuminator IL may include an adjuster AD for adjusting the angular intensity distribution of the radiation beam. In general, at least the outer and / or inner radial extent (commonly referred to as σ-outer and σ-inner, respectively) of the intensity distribution in the illuminator pupil plane can be adjusted. In addition, the illuminator IL may include various other components such as an integrator IN and a capacitor CO. By adjusting the radiation beam using an illuminator, the desired uniformity and intensity distribution can be provided in the cross section of the radiation beam.

  [0033] The radiation beam B is incident on the patterning device (eg, mask MA), which is held on the support structure (eg, mask table MT), and is patterned by the patterning device. After passing through the mask MA, the radiation beam B passes through the projection system PL, which focuses the beam onto the target portion C of the substrate W. The second positioner PW and the position sensor IF (eg interferometer device, linear encoder, 2-D encoder or capacitive sensor) are used, for example, to position various target portions C in the path of the radiation beam B. In addition, the substrate table WT can be moved accurately. Similarly, using the first positioner PM and another position sensor (not explicitly shown in FIG. 1a), for example after mechanical removal from the mask library or during a scan, the mask MA is emitted by the radiation beam B It is also possible to accurately position relative to the path. In general, the movement of the mask table MT can be achieved by using a long stroke module (coarse positioning) and a short stroke module (fine positioning) that form part of the first positioner PM. Similarly, movement of the substrate table WT can also be achieved using a long stroke module and a short stroke module that form part of the second positioner PW. In the case of a stepper (as opposed to a scanner) the mask table MT may be connected to a short stroke actuator only, or may be fixed. Mask MA and substrate W may be aligned using mask alignment marks M1 and M2 and substrate alignment marks P1 and P2. In the example, the substrate alignment mark occupies the dedicated target portion, but the substrate alignment mark can also be placed in the space between the target portion (these are known as scribe line alignment marks). Similarly, if a plurality of dies are provided on the mask MA, the mask alignment mark may be placed between the dies.

[0034] The example apparatus can be used in at least one of the modes described below.
1. In step mode, the entire pattern applied to the radiation beam is projected onto the target portion C at once (ie, a single static exposure) while the mask table MT and substrate table WT remain essentially stationary. Thereafter, the substrate table WT is moved in the X and / or Y direction so that another target portion C can be exposed. In step mode, the maximum size of the exposure field limits the size of the target portion C imaged during a single static exposure.
2. In scan mode, the mask table MT and substrate table WT are scanned synchronously while a pattern imparted to the radiation beam is projected onto a target portion C (ie, a single dynamic exposure). The speed and direction of the substrate table WT relative to the mask table MT can be determined by the (reduction) magnification factor and image reversal characteristics of the projection system PL. In the scan mode, the maximum size of the exposure field limits the width of the target portion during single dynamic exposure (non-scan direction), while the length of the scan operation determines the height of the target portion (scan direction). Determined.
3. In another mode, while holding the programmable patterning device, the mask table MT remains essentially stationary and the substrate table WT is moved or scanned while the pattern attached to the radiation beam is targeted. Project onto part C. In this mode, a pulsed radiation source is typically employed, and the programmable patterning device can also be used after each movement of the substrate table WT or between successive radiation pulses during a scan as needed. Updated. This mode of operation can be readily applied to maskless lithography that utilizes programmable patterning device, such as a programmable mirror array of a type as described above.

  [0035] Combinations and / or variations on the above described modes of use or entirely different modes of use may also be employed.

  [0036] As shown in FIG. 2, the lithographic apparatus LA forms part of a lithographic cell LC, sometimes referred to as a lithocell or cluster, which also includes apparatus for performing pre-exposure and post-exposure processes on the substrate. . Conventionally, these include a spin coater SC for depositing a resist layer, a developer DE for developing an exposed resist, a cooling plate CH, and a bake plate BK. The substrate handler or robot RO picks up the substrate from the input / output ports I / O1 and I / O2, moves it between the different process devices, and then delivers it to the loading bay LB of the lithographic apparatus. These devices are often collectively referred to as tracks and are under the control of the track control unit TCU, which is itself controlled by the supervisory control system SCS, which also controls the lithographic apparatus via the lithography control unit LACU. Thus, various devices can be operated to maximize throughput and processing efficiency.

  [0037] In order to accurately and consistently expose the substrate exposed by the lithographic apparatus, the exposed substrate is inspected for characteristics such as overlay errors between subsequent layers, line thickness, critical dimension (CD), etc. It is desirable to measure. If an error is detected, the exposure of subsequent substrates can be adjusted, especially if the inspection can be performed immediately and quickly enough to still expose other substrates in the same batch. Also, an already exposed substrate can be removed and reworked (to improve yield) or discarded, thereby avoiding performing an exposure on a substrate that is known to be defective. If only some target portions of the substrate are defective, further exposure can be performed only on the good target portions.

  [0038] An inspection device is used to determine the properties of the substrate, particularly how the properties of different substrates or different layers of the same substrate differ from layer to layer. The inspection apparatus may be integrated into the lithographic apparatus LA or the lithocell LC or may be a stand-alone device. In order to enable the quickest measurement, it is desirable that the inspection apparatus measures the characteristics of the exposed resist layer immediately after exposure. However, the latent image of the resist has a very low contrast, and the refractive index of the resist portion exposed by radiation and the unexposed portion must be very small. It does not have enough sensitivity to measure. Thus, the measurement can be performed after a post-exposure bake step (PEB), which is the first step performed on a customarily exposed substrate and improves the contrast between the exposed and unexposed portions of the resist. At this stage, the image in the resist can be called semi-potential. It is also possible to measure the developed resist image when either the exposed or unexposed portions of the resist are removed or after a pattern transfer step such as etching. The latter possibility limits the possibility of reworking a defective substrate, but can still provide useful information.

  [0039] FIG. 3 shows a scatterometer SM1 that can be used in the present invention. The scatterometer SM1 includes a broadband (white light) radiation projector 2 that projects radiation onto the substrate W. The reflected radiation is passed to the spectroscopic detector 4 which measures the spectrum 10 (intensity as a function of wavelength) of the specularly reflected radiation. From this data, the structure or profile that gives rise to the detected spectrum is reconstructed by the processing unit PU, for example by rigorous coupled wave analysis and nonlinear regression, or by comparison with a library of simulated spectra as shown at the bottom of FIG. Can be built. In general, to reconstruct, the overall form of the structure is known, some parameters are assumed from the knowledge of the process that created the structure, and only some parameters of the structure are scatterometer data. Is left to ask. Such a scatterometer can be configured as a normal incidence scatterometer or an oblique incidence scatterometer.

  [0040] Another scatterometer SM2 that can be used in the present invention is shown in FIG. In this device, the radiation emitted by the radiation source 2 is focused through the interference filter 13 and the polarizer 17 using the lens system 12 and reflected by the partially reflective surface 16, and then preferably at least 0.9, more preferably Are focused on the substrate W via the objective lens 15 of the microscope having a high numerical aperture (NA) of at least 0.95. The immersion scatterometer may have a lens with a numerical aperture greater than one. The reflected radiation then passes through the partially reflective surface 16 and enters the detector 18 to detect the scattered spectrum. The detector can be placed in the rear projection pupil plane 11, which is at the focal length of the lens system 15. However, the pupil plane can also be re-imaged onto the detector by an auxiliary optical system (not shown). The pupil plane is a plane in which the radial position of the radiation defines the incident angle and the angular position defines the azimuth angle of the radiation. The detector is preferably a two-dimensional detector so that the two-dimensional angular scattering spectrum of the substrate target 30 can be measured. The detector 18 is, for example, a CCD or CMOS sensor array and uses, for example, an integration time of 40 milliseconds per frame.

  [0041] A reference beam is often used, for example, to measure the intensity of incident radiation. To do so, when the radiation beam is incident on the beam splitter 16, a portion of it passes through the beam splitter as a reference beam toward the reference mirror. The reference beam is then projected onto a different part of the same detector 18.

  [0042] For example, a set of interference filters 13 can be used to select a wavelength of interest in the range of 405 to 790 nm or even lower ranges such as 200 to 300 nm. The interference filter may be adjustable rather than including a different set of filters. A diffraction grating can also be used instead of the interference filter.

  [0043] The detector 18 measures the intensity of scattered light at a single wavelength (or narrow wavelength range), measures the intensity separately at multiple wavelengths, or measures the intensity integrated over a range of wavelengths. can do. Furthermore, the detector can measure separately the intensity of TM (transverse magnetic) polarization and the intensity of TE (transverse electric) polarization and / or the phase difference between TM polarization and TE polarization.

  [0044] A broadband light source (ie, a light source with a frequency or wavelength of light and therefore a wide color range) can be used, which gives a large etendue and allows for the mixing of multiple wavelengths. Each of the multiple wavelengths in the broadband is || bandwidth and at least 2. It is preferred to have an interval of || (ie twice the bandwidth). Some radiation “sources” may be different parts of an extended radiation source that is split using fiber bundles. By this method, the angle-resolved scattering spectrum can be measured in parallel at a plurality of wavelengths. A 3-D spectrum (wavelength and two different angles) can be measured, and the 3-D spectrum contains more information than the 2-D spectrum. This makes it possible to measure more information and improve the robustness of the metrology process. This is described in more detail in EP 1,628,164A, the entirety of which is incorporated herein by reference.

  The target 30 on the substrate W may be a diffraction grating printed so that a bar is formed by a solid line of resist after development. Alternatively, the bar can be etched into the substrate. This pattern is sensitive to the chromatic aberration of the lithographic projection apparatus, in particular the projection system PL, and the symmetry of the illumination and the presence of such aberrations manifest as variations in the printed diffraction grating. Therefore, the diffraction grating is reconstructed using the printed diffraction grating scatterometry data. From knowledge of the printing step and / or other scatterometry processes, diffraction grating parameters such as line width and shape can be entered into the reconstruction process and executed in the processing unit PU.

  The pattern to be exposed on the substrate W includes product features 40 and overlay mark features 45. Product features have the smallest pitch of about tens of nanometers, especially 80 nm. As shown in FIG. 5 (not to scale), overlay mark features are much larger than product features, such as about tens of microns. However, according to one embodiment of the present invention, the overlay mark has subfeatures 46 having the smallest pitch that is equivalent to the smallest pitch of product features 40, as shown in FIG. As shown in the figure, the pitch of the product feature and the subfeature is the same, but the critical dimension of the subfeature is larger. The subfeature 46 has the same aberration sensitivity and other distortion sensitivity as the product feature because the product feature 40 and subfeature 46 have an equivalent pitch when the patterned projection beam is projected through the projection system.

  [0047] The patterned projection beam exposes a radiation sensitive material on the substrate, which is then developed. During development, the outline of the product feature is exposed. However, due to the larger critical dimension, the subfeatures combine with a single (large) overlay feature. The features, including overlay features, are then etched into the substrate, and the use of larger scale features in the overlay features results in a structure that has a high contrast when measured. The overlay feature can then be used in a scatterometer to determine the overlay error for another overlay feature.

  [0048] The smallest pitch of the subfeature should be approximately the same as the order of the smallest pitch of the product feature. It will be appreciated by those skilled in the art that the smallest pitch should be as close as possible and approximately equal, but need not be exactly the same.

  [0049] Preferably, every overlay feature on every feature of the substrate should have a sub-feature with the smallest pitch that is approximately equal to the smallest pitch of the product features in the layer of interest.

  [0050] Although the present invention has been described with respect to the use of overlay marks, the same design may be used for overlay marks having similar subfeatures.

  [0051] Although specific reference is made herein to the use of a lithographic apparatus in IC manufacture, the lithographic apparatus described herein is an integrated optical system, a guidance pattern and a detection pattern for a magnetic domain memory, It should be understood that other applications such as the manufacture of flat panel displays, liquid crystal displays (LCDs), thin film magnetic heads and the like may be had. As will be appreciated by those skilled in the art, in such other applications, the terms “wafer” or “die” as used herein are all more general “substrate” or “target” respectively. It may be considered synonymous with the term “part”. The substrate described herein can be used, for example, before or after exposure, such as a track (usually a tool for applying a resist layer to the substrate and developing the exposed resist), a metrology tool, and / or an inspection tool. May be processed. Where applicable, the disclosure herein may be applied to substrate processing tools such as those described above and other substrate processing tools. Further, since the substrate may be processed multiple times, for example, to make a multi-layer IC, the term substrate as used herein may refer to a substrate that already contains multiple processing layers.

  [0052] Although specific reference has been made to the use of embodiments of the present invention in the context of optical lithography as described above, it will be appreciated that the present invention may be used in other applications, such as imprint lithography. However, it is not limited to optical lithography if the situation permits. In imprint lithography, the topography within the patterning device defines the pattern that is created on the substrate. The topography of the patterning device is pressed into a resist layer supplied to the substrate, whereupon the resist is cured by electromagnetic radiation, heat, pressure, or a combination thereof. The patterning device is moved out of the resist leaving a pattern in it after the resist is cured.

  [0053] As used herein, the terms "radiation" and "beam" refer to ultraviolet (UV) (eg, wavelengths of 365 nm, 355 nm, 248 nm, 193 nm, 157 nm, or 126 nm, or approximately these wavelengths) ), And extreme ultraviolet (EUV) (e.g., having a wavelength in the range of 5-20 nm), and all types of electromagnetic radiation, including particulate beams such as ion beams and electron beams.

  [0054] The term "lens" may refer to any one or combination of various types of optical components, including refractive, reflective, magnetic, electromagnetic, and electrostatic optical components, depending on the context. .

  [0055] While specific embodiments of the invention have been described above, it will be appreciated that the invention may be practiced otherwise than as described. For example, the invention may be in the form of a computer program comprising a sequence of one or more machine-readable instructions representing the methods disclosed above, or a data storage medium (eg, semiconductor memory, magnetic A disc or an optical disc).

Conclusion
[0056] The Summary and Summary section may describe one or more exemplary embodiments of the invention as contemplated by the inventor (s), but describes all exemplary embodiments. Therefore, it is not intended to limit the invention and the appended claims in any way.

  [0057] The present invention has been described above using functional components and relationships that illustrate the implementation of particular functions. The boundaries of these functional components are arbitrarily defined herein for convenience of explanation. Alternative boundaries can be defined as long as certain functions and relationships are properly performed.

  [0058] The foregoing description of specific embodiments sufficiently clarifies the overall nature of the present invention, so that by applying the knowledge in the art, without undue experimentation, the entire Such particular embodiments can be easily modified and / or adapted to various applications without departing from the general concept. Accordingly, such adaptations and modifications are intended to fall within the meaning and scope of the equivalents of the disclosed embodiments based on the teachings and guidance presented herein. It should be understood that the terminology or terms herein is for purposes of illustration and not limitation, and that terminology or terms herein should be construed in terms of teaching and guidance to those skilled in the art. .

  [0059] The breadth and scope of the present invention are not limited by any of the above-described exemplary embodiments, but are defined only by the following claims and their equivalents.

Claims (18)

A method for measuring properties, said method comprising:
(A) projecting a radiation beam having a pattern onto a substrate, the pattern comprising a product comprising a plurality of product features and a mark comprising a plurality of mark features, wherein at least one feature comprises a plurality of subfeatures; Including,
(B) forming the pattern on the substrate;
(C) projecting a radiation beam onto the pattern;
(D) detecting a diffraction pattern from the pattern;
(E) determining an overlay error between the pattern and a lower layer pattern based on the diffraction pattern;
The subfeature has a pitch that is substantially equal to the pitch of the product feature, and when the pattern is formed, the mark feature and the product feature outline are formed, but the shape of the subfeature is The method that is not formed.   The method of claim 1, wherein forming the pattern on the substrate comprises etching the pattern into the substrate.   The method of claim 1, wherein forming the pattern on the substrate comprises forming the pattern in a radiation sensitive layer on the substrate.   4. The method of claim 3, wherein forming the pattern on the substrate comprises developing the radiation sensitive layer on the substrate.   The method of claim 1, wherein the product features have a plurality of pitches.   The method of claim 5, wherein the subfeature has a pitch that is substantially equal to a smallest pitch of the product features.   The method of claim 1, wherein the pitch of the subfeatures and the product features is 80-100 nm. A method for measuring properties, said method comprising:
(A) projecting a radiation beam having a pattern onto a substrate, the pattern comprising a product comprising a plurality of product features and a mark comprising a plurality of mark features, wherein at least one feature comprises a plurality of subfeatures; Including,
(B) forming the pattern on the substrate;
The subfeature has the smallest pitch that is equal to the pitch of the product feature, and when the pattern is formed, the mark feature and the product feature outline are formed, but the shape of the subfeature is formed Not the way. A device manufacturing method comprising:
(A) projecting a radiation beam having a pattern onto a substrate, the pattern comprising a product comprising a plurality of product features and a mark comprising a plurality of mark features, wherein at least one feature comprises a plurality of subfeatures; Including,
(B) forming the pattern on the substrate;
The subfeature has the smallest pitch that is equal to the pitch of the product feature, and when the pattern is formed, the mark feature and the product feature outline are formed, but the shape of the subfeature is formed Not a device manufacturing method. Projecting a radiation beam having a pattern onto a substrate, the pattern comprising a product comprising a plurality of product features and a mark comprising a plurality of mark features, wherein at least one feature comprises a plurality of subfeatures; When,
Forming the pattern on the substrate;
Projecting a beam of radiation onto the pattern;
Detecting a diffraction pattern from the pattern;
Determining an overlay error between the pattern and an underlying pattern based on the diffraction pattern;
The subfeature has a pitch that is substantially equal to the pitch of the product feature, and when the pattern is formed, the mark feature and the product feature outline are formed, but the shape of the subfeature is The method that is not formed.   The method of claim 10, wherein forming the pattern on the substrate comprises etching the pattern into the substrate.   The method of claim 10, wherein forming the pattern on the substrate comprises forming the pattern in a radiation sensitive layer on the substrate.   The method of claim 12, wherein forming the pattern on the substrate comprises developing the radiation sensitive layer on the substrate.   The method of claim 10, wherein the product features have a plurality of pitches.   The method of claim 14, wherein the subfeature has a pitch that is substantially equal to a smallest pitch of the product features.   The method of claim 10, wherein the pitch of the subfeatures and the product features is 80-100 nm. Projecting a radiation beam having a pattern onto a substrate, the pattern comprising a product comprising a plurality of product features and a mark comprising a plurality of mark features, wherein at least one feature comprises a plurality of subfeatures; When,
Forming the pattern on the substrate,
The subfeature has the smallest pitch that is equal to the pitch of the product feature, and when the pattern is formed, the mark feature and the product feature outline are formed, but the shape of the subfeature is formed Not the way. A device manufacturing method comprising:
Projecting a radiation beam having a pattern onto a substrate, the pattern comprising a product comprising a plurality of product features and a mark comprising a plurality of mark features, wherein at least one feature comprises a plurality of subfeatures; When,
Forming the pattern on the substrate,
The subfeature has the smallest pitch that is equal to the pitch of the product feature, and when the pattern is formed, the mark feature and the product feature outline are formed, but the shape of the subfeature is formed Not a device manufacturing method.

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